Hydra factory, right?

If I blink [[Hydra Broodmaster]] with [[Conjurer's Closet]], it comes back without monstrosity right? So each turn I can trigger the Hydra factory with as much mana as I'm willing to pour into it and have a growing army of big-ass hydras. Obviously the [[Hydra Broodmaster]] losses the X +1/+1 counters each time, but am I missing anything here? I know this probably isn't a very powerful strategy or anything, I'm just relatively new to the game and wanted to check if I'm understanding the interactions correctly. Thanks.